The present disclosure relates to a battery comprising at least two battery cells which are arranged adjacent to one another and which have in each case one degasification element, wherein the battery also comprises a cover which is configured to cover at least a part of the surfaces of the battery cells and cover the degasification elements of the battery cells in air-tight fashion and which has, in each case in the region of the degasification elements, predetermined breaking points that can be assigned to the degasification elements.
Battery packs or batteries, in particular lithium-ion battery packs or lithium-ion batteries for automotive applications, are presently manufactured from lithium-ion battery cells in VDA hard-case form. In other words, the batteries of the prior art nowadays have in particular lithium-ion battery cells arranged in each case in so-called hard-case battery cell housings, that is to say in battery cell housings that have a hard shell. Battery cells of said type normally have a battery cell housing which is composed partially or entirely of aluminum. To increase the voltage that can be provided by the battery packs or batteries, and/or to increase the current that can be provided by the battery packs or batteries, the individual battery cells within the battery pack or within the battery are connected in series and/or in parallel with one another to form battery modules. Said battery modules may then in turn be connected to one another to form battery packs or batteries.
Improper handling, for example overloading, damage or for example construction faults that lead for example to short circuits within the battery or contamination, can cause the batteries or the battery cells thereof to pass into a critical state. If the batteries or the individual battery cells are then not freed from said state in good time, this can lead to thermal runaway of the battery cells and thus to severe damage thereof. For this reason, in the prior art, so-called degasification elements are installed within the battery cell housings of the battery cells, which degasification elements are in each case configured to discharge gases generated within the respective battery cell from the respective battery cell in the presence of a predetermined gas pressure. In this way, gases and entrained particles are thus discharged from a, for example damaged, battery cell in the presence of a predetermined overpressure, and thus thermal runaway of said battery cell is prevented. In general, said process is associated with intense generation of heat. Here, degassing of a battery cell with the degasification element open normally takes place directly into the battery or into the battery pack in which the respective battery cell is installed. Alternatively, the escaping gas is accumulated and discharged via open or closed systems such as, for example, degasification ducts.
In the case of such systems, however there is in turn the risk of the substances that escape from a damaged battery cell attacking adjacent battery cells and of the temperature of the hitherto intact battery cells increasing into an inadmissible range, whereby the latter battery cells may likewise be damaged, as a result of the generation of heat within the battery or within the battery pack. For example, U.S. 2012/00941564 A1 describes a system of said type or a device for protecting the battery cells in the event of degassing, wherein the degasification elements of the battery cells, which in U.S. 2012/00941564 A1 are in the form of rupture diaphragms, are situated in an unprotected location within a degasification duct.